1. Field of the Invention
The present invention relates to a marker buoy and more specifically to a buoy used to mark the location of a submerged anchor.
2. Description of the Related Art
When a small boat 10 such as shown in FIG. 1 is to be moored, an anchor locating line 30 is typically fastened between a marker float 20 (which may be as simple as an empty plastic bottle) and a tripping point 45 of an anchor 40 before dropping the anchor 40 into the water. Referring to FIG. 2, it can be seen that after the anchor 40 submerges and catches hold of an anchorage fixture 70 at a vertical depth D below the water surface 5, the anchor locating float 20 remains within a circular marking perimeter 65 above the submerged anchor 40. The diameter of the marking perimeter 65 is dependent on the difference between the length L of the locating line 30 and the vertical depth D at the particular anchorage site. If the line 30 is made too short (i.e., L&lt;D), the float 20 will become completely submerged such that it is no longer visible and thus not functional.
The locating line 30 is often formed by measuring out a fixed length L of cord that is slightly longer than an expected water depth D at the anchorage site. Opposed ends of the cord are then fastened to the tripping point 45 of the anchor and to a float 20, and the float 20 is tossed overboard before dropping anchor. As the anchor drops, a length of anchor chain 50, which is longer than the vertical depth D, and is attached to a load point 47 on the anchor 40, is paid out to create slack in the anchor chain 50. The slack allows the anchor chain 50 to exert a desirable, substantially non-vertical pull on the load point 47 once the anchor 40 catches hold of an anchorage fixture 70. This non-vertical arrangement enhances the anchor's holding power.
While it remains moored to the submerged anchor 40, the boat 10 will generally drift to the peripheral edge of a circular anchorage perimeter 60 as a result of prevailing winds and/or water currents. When it is time to break anchor, the boat 10 is brought back to the location marked by the anchor locating float 20 and the locating line 30 is pulled to apply a substantially vertical force to the tripping point 45 of the anchor in order to free the anchor from the underwater anchorage fixture 70. The anchor chain 50 is then hauled in to raise the anchor 40. The locating line 30 is generally pulled in by hand afterwards to retrieve the anchor locating float 20 before the boat 10 gets under way.
Although the above described procedure is relatively simple, several things may go awry. When the motor of the boat 10 is shut off for example, there is usually some wind or water current at the anchorage site which will swing the boat about so its bow 12 points into the current and the propeller 14 (not shown) projects under water in the other direction. The boat 10 drifts freely in this manner until the anchor 40 is dropped and attached to a submerged anchorage fixture 70. There may be projecting rocks near by or other boats in the vicinity that are to be avoided while the boat drifts freely. It is desirable to drop the anchor 40 as quickly as possible before the boat 10 drifts too close to these neighboring objects. After the marker float 20 (FIG. 1) is thrown overboard while preparing to lower the anchor 40, the prevailing winds or water currents can pull the marker float 20 back towards the propeller 14 in such a manner that the locating line 30 is fouled in the propeller 14. The boat 10 may continue to drift toward the neighboring danger points while time is consumed trying to free the fouled locating line 30. The same problem may occur when the anchor 40 is raised. Water or wind currents can pull the marker float 20 back behind the boat 10 while the anchor is being raised. The locating line 30 can again become entangled in the propeller 40 before the boat 10 gets underway.
Another problem occurs when the locating line 30 is measured out to the aforementioned fixed length L before the anchor 40 is dropped. The measured length L of the locating line 30 is preferably fixed so it will be slightly longer than the vertical depth D of the anchorage site so the float 20 will remain above water and the diameter of the marking perimeter 65 will be small. Accurate prediction of the vertical depth D is difficult however. There is no simple method for determining the depth of a yet unknown anchorage fixture 70 to which the anchor 40 will eventually attach after the anchor is dropped. Moreover, the vertical depth D varies with time as weather conditions and tide levels change. If an incorrect guess is made on the first drop of the anchor and the fixed length L of the locating line 30 is measured out to be shorter than the actual vertical depth D, the float 20 will be completely submerged and the anchor 40 must then be pulled back up so additional length can be added to the locating line 30. The boat 10 is free to drift in undesirable directions while the locating line 30 is being adjusted.
Often, it is desirable to power the propeller 14 as soon as the anchor 40 is pulled safely away from an anchorage fixture 70 so the boat 10 can get underway quickly. With the above described method, however, the anchor 40 must be pulled completely out of the water and the locating line 30 retrieved by hand before it is safe to turn on the propeller 14 so the danger of fouling the locating line 30 in the propeller 14 is avoided. In addition to being time consuming, the manual operation of retrieving the locating line 30 is inconvenient and unreliable. The last step of retrieving the line 30 is often forgotten while attempting to get underway quickly and the locating line 30 may then become fouled in the propeller 14 after the boat 10 starts to move. This causes additional delay and again raises the danger of undesirable collision with nearby objects while the boat drifts without power. An anchor marking system that avoids these problems would make leisure boating both safer and more enjoyable.